Create a rounded wireframe?
Yes this is possible, the wire-frame tool has a Crease toggle, that gives a nicer result when the subsurf modifier is applied.

With Crease option enabled (right).

Note:
there is a bug in 2.68a, where this option only works if creases were already added to the mesh. Fixed in trunk (available in any builds newer than r60061 and will be in 2.69).
To workaround this you can add a crease to any edge before accessing wire tool.